Index: /trunk/src/org/openstreetmap/josm/actions/SimplifyWayAction.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/actions/SimplifyWayAction.java	(revision 12385)
+++ /trunk/src/org/openstreetmap/josm/actions/SimplifyWayAction.java	(revision 12386)
@@ -218,5 +218,5 @@
         newWay.setNodes(newNodes);
         cmds.add(new ChangeCommand(w, newWay));
-        cmds.add(new DeleteCommand(delNodes));
+        cmds.add(new DeleteCommand(w.getDataSet(), delNodes));
         w.getDataSet().clearSelection(delNodes);
         return new SequenceCommand(